New Zealand

Restoration initiatives of ecosystems transformed by human actions require optimisation of eradication measures of introduced species, particularly in fragile insular ecosystems. We studied aspects of the spatial ecology of introduced feral cats (Felis catus) on subantarctic Auckland Island of New Zealand to assist eradication efforts of pests from this remote, biologically rich island. Firstly, we estimated home range sizes and identified core areas of activity based on movement-rooted dynamic Brownian bridge models.

The advent of mammal-resistant fences has allowed multi-species eradications of mammals from ecosanctuaries on the New Zealand mainland. However, maintaining eradication of house mice (Mus musculus) has proven difficult, and at some fenced reserves they are the only exotic mammal present and reach a high population density. Over 5 years we examined the impacts of mice alone on biodiversity at Sanctuary Mountain Maungatautari by comparing forest blocks with relatively high and low numbers of mice.

The introduction of mammalian predators, particularly stoats (Mustela erminea), to New Zealand led to the decline in whio (Hymenolaimus malacorhynchos), an endemic riverine duck. Stoat control for whio in the South Island has focused on valley floor trapping along waterway margins but increasing survival and productivity for whio using this method is complicated by irruptive predator dynamics caused by occasional masting of beech species (Nothofagaceae).

Biodiversity conservation in Aotearoa New Zealand is of high importance, and efforts to protect vulnerable populations from decline has garnered broad public support. Conservation efforts have been further highlighted with the 2016 announcement of Predator Free 2050, a nationwide goal to eliminate key invasive mammalian predators from New Zealand by the year 2050. Hands-on labour is often needed to complete conservation initiatives, and New Zealand conservation volunteers have shown themselves to be an abundant, effective, and oft-used workforce.

Stable isotope analysis of feathers can provide an indirect method to investigate the diet and foraging locations of birds during the time the feathers were growing. We used the isotopic composition of experimentally-induced feathers to investigate the foraging locations of the Hutton’s shearwater (Puffinus huttoni), an endangered seabird that is a breeding endemic to the Kaikōura region of New Zealand. The isotopic composition of feathers was first compared with potential prey items collected from the near-shore marine environment near the breeding colony.

The pre-human moa fauna of Rakiura Stewart Island is poorly known, and although there is little clear evidence that moa occurred naturally on the island, isolated moa bones are often found associated with archaeological middens. Here we report the discovery and collection of what is likely a naturally deposited partial South Island giant moa (Dinornis robustus) skeleton from West Ruggedy Beach, Rakiura, radiocarbon dated to 1297–1395 CE (95.4% CI). The time of death of this moa overlaps with the early occupation of the island by Māori.

To be considered an effective pollinator, a floral visitor must not only be able to remove pollen but also transfer this pollen to a receptive conspecific stigma. While studies of diurnal pollination are commonplace, our understanding of the effectiveness of nocturnal pollinators is limited largely because of the difficulties of doing these studies at night. As a result of this, the way in which moths transfer pollen between flowers has been understudied globally, despite many authors suggesting they could be significant contributors to pollination.

Recent advances in the control of mammalian predators have begun to reveal interspecific competition as a key driver in the structure of New Zealand forest bird communities once predation pressure is reduced. We present evidence that, when at high densities, South Island robins (Petroica australis) may be responsible for declines in a suite of smaller native and introduced songbird species. Bird surveys undertaken on 47 islands in Breaksea Sound and Dusky Sound, Fiordland, during 1974 to 1986, were repeated on the same islands in 2016 or 2019.

For tens of millions of years the ratite moa (Aves: Dinornithiformes) were the largest herbivores in New Zealand’s terrestrial ecosystems. In occupying this ecological niche for such a long time, moa undoubtedly had a strong influence on the evolution of New Zealand’s flora and played important functional roles within ecosystems. The extinction of moa in the 15th century ce therefore marked a significant event in New Zealand’s biological history, not only in terms of biodiversity loss, but in the loss of an evolutionarily and ecologically distinct order of birds.

New Zealand has a unique opportunity to reshape the future of 1.2 million hectares, or 5% of the country. Since 1990, land clearance and development in the South Island high country have removed large areas of native vegetation, destroying already tenuous endemic species populations, and rare and threatened ecosystems. Important ecosystems and ecological values have been subtly or dramatically degraded through tenure review, discretionary consents, and invasions of plant and animal pests.